On-line commerce, which can be referred to as e-commerce, has over the years achieved widespread acceptance thanks to the expansive growth of the Internet and the growing sophistication of on-line merchant systems. Consumers today can purchase goods or services from on-line merchants over secure communication interfaces operating according to protocols such as a Hypertext Transfer Protocol Secure (HTTPS). E-commerce transactions using the HTTPS protocol usually show an iconic symbol such as a “pad lock” somewhere in the browser window to indicate to the user that the communication with the on-line merchant is secure.
Sophisticated e-commerce systems have provided users a means to purchase or sell goods by fixed price or auctioning methods. Many retailers today also offer their consumers the convenience to purchase their products over on-line systems. To enhance a user's security in e-commerce transactions, payments systems such as PayPal™ can be used to protect the privacy of sensitive consumer information such as bank accounts and credit card information during an e-commerce transaction.